Before you start stock trading: first think if it is worth your time and money.
That was the good news. The bad news is that those companies are selling you the tools and service only. They do not sell you any guarantees of success. It does not matter if you profit or lose money, the trading company will get its fee for each trade anyway.
Since you are considering going into the stock market, most likely you are planning to get a significant return on your investment which should also be better than what you would get buy investing your money into mutual funds (less risky than single stocks) or even no-risk certificate of deposits (CDs) where returns are guaranteed.
Well, how can you get such returns? The answer of course is simple and well known: buy low, sell high. If you do it most of the time youll be a successful stock trader. Now the first problem comes: how do you know when to buy? There are probably several ways to do that, we do not discuss this here, lets assume that you know somehow or think you do know. Lets say you got lucky and the stock after you bought it is going up, just as you planned.
Now another problem comes: when to sell?...